DevTools: [HeapProfiler] Provide API for heap objects tracking info.

LayoutTests/inspector-protocol/heap-profiler/resources/heap-snapshot-common.js

 // This script is supposed to be evaluated in dummy inspector front-end which is loaded from
 // ../../../http/tests/inspector-protocol/resources/protocol-test.html and the relative paths
 // below are relative to that location.
 
 if (!window.WebInspector)
     window.WebInspector = {};
 InspectorTest.importScript("../../../../../Source/devtools/front_end/HeapSnapshot.js");
 InspectorTest.importScript("../../../../../Source/devtools/front_end/JSHeapSnapshot.js");
 
+InspectorTest.fail = function(message)
+{
+    InspectorTest.log("FAIL: " + message);
+    InspectorTest.completeTest();
+}
+
+InspectorTest.assert = function(result, message)
+{
+    if (!result)
+        InspectorTest.fail(message);
+}
+
 InspectorTest.takeHeapSnapshot = function(callback)
 {
     InspectorTest.eventHandler["HeapProfiler.addProfileHeader"] = function(messageObject)
     {
         var profileId = messageObject["params"]["header"]["uid"];
         InspectorTest.sendCommand("HeapProfiler.getHeapSnapshot", { "uid": profileId }, didGetHeapSnapshot);
 
         function didGetHeapSnapshot(messageObject)
         {
             InspectorTest.log("SUCCESS: didGetHeapSnapshot");
@@ skipping 10 matching lines @@
     InspectorTest.eventHandler["HeapProfiler.finishHeapSnapshot"] = function(messageObject)
     {
         var serializedSnapshot = chunks.join("");
         var parsed = JSON.parse(serializedSnapshot);
         var snapshot = new WebInspector.JSHeapSnapshot(parsed);
         callback(snapshot);
     }
 
     InspectorTest.sendCommand("HeapProfiler.takeHeapSnapshot", {});
 }